A growing body of work has demonstrated that maternal stress plays a pivotal role in shaping maternal, infant, and child health outcomes. Due to their stigmatized status, sexual minority women (SMW; those with same-sex attractions, same-sex behavior, and/or a lesbian/gay/bisexual identity) are exposed to a variety of stressors, both interpersonal and institutional, above and beyond those experienced by the general population, including high rates of physical and sexual violence, familial rejection, employment discrimination, as well the historical lack of legal recognition for same-sex relationships. These forms of minority stress are known to have negative consequences for SMW?s mental and physical health, however, the implications of minority stress for SMW?s maternal and infant health is unclear. This study builds on existing research conducted with racial/ethnic minorities that has demonstrated the negative effects of both interpersonal and institutional discrimination on maternal, infant and child health, as well as the positive consequences of repealing discriminatory policies (e.g. Jim Crow, passing the Civil Rights Act) for maternal and infant health. Using the National Longitudinal Study of Adolescent to Adult Health (Add Health), a nationally representative, prospectively collected data set, this study will examine sexual orientation disparities in perinatal health behaviors as well as maternal, infant, and child health outcomes. Additionally, this study will be the first to investigate the role of both interpersonal and institutional discrimination for shaping SMW?s fetal and maternal outcomes. The first wave of Add Health data collection occurred in 1994-1995, when women were between 12 to 20 years old, the most recent wave of data collection (2006-2007) spans ages 24 through 32, and the upcoming Wave V of data collection will cover ages 34 through 40, spanning the majority of women?s reproductive years. To date, 13,706 pregnancies have been reported in the data, of which 3,683 were reported by SMW. Data from Wave V, which is currently being collected, will allow us to compare maternal, infant, and child health outcomes pre- and post-same-sex marriage legalization to determine whether the recent nationwide legalization of same-sex marriage has led to improvements in SMW?s reproductive outcomes. Preliminary results using these data show significantly higher prevalence of reported alcohol and tobacco use among SMW, and almost double the prevalence of preterm (28.1% vs. 16%) and low birth weight (28.7% vs. 10%) infants among lesbian compared to heterosexual women. These preliminary data suggest a critical and immediate need for further investigation of maternal and infant health disparities and the underlying mechanisms that contribute to excess risk. This research will therefore make a significant contribution to scientific and policy efforts to reduce the health disparities faced by SMW and their children.